One of the great debates surrounding insanity is whether it is an excuse for criminal defendants designed to exculpate otherwise guilty people or whether it is a device used by the government to inculpate otherwise innocent people. The short answer is both. Sometimes, insanity is used to exculpate someone who is otherwise guilty, while other times, the state successfully chooses to punish those who, because of their insane delusions, lack criminal intent.
In my view, insanity should rarely exculpate and never implicate. Thus, on the one hand, when insanity is invoked as a defense by one who has been proven guilty of the requisite mens rea and actus reus for the crime, insanity should rarely, if ever, exculpate. On the other hand, when the defendant lacks the requisite mens rea to commit the crime, whether because of insanity or any other non-self-induced reason, the defendant should not be guilty.